Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published May 11, 2016 | Supplemental Material
Journal Article Open

Proton-Assisted Reduction of CO_2 by Cobalt Aminopyridine Macrocycles

Abstract

We report here the efficient reduction of CO_2 to CO by cobalt aminopyridine macrocycles. The effect of the pendant amines on catalysis was investigated. Several cobalt complexes based on the azacalix[4](2,6)pyridine framework with different substitutions on the pendant amine groups have been synthesized (R = H (1), Me (2), and allyl (3)), and their electrocatalytic properties were explored. Under an atmosphere of CO_2 and in the presence of weak Brønsted acids, large catalytic currents are observed for 1, corresponding to the reduction of CO_2 to CO with excellent Faradaic efficiency (98 ± 2%). In comparison, complexes 2 and 3 generate CO with TONs at least 300 times lower than 1, suggesting that the presence of the pendant NH moiety of the secondary amine is crucial for catalysis. Moreover, the presence of NH groups leads to a positive shift in the reduction potential of the Co^(I/0) couple, therefore decreasing the overpotential for CO_2 reduction.

Additional Information

© 2016 American Chemical Society. Received: February 22, 2016. Published: April 19, 2016. This work was supported by the University of Southern California and the National Science Foundation (NSF) through the NSF CAREER award (CHE–1555387). We are grateful to the USC Wrigley Institute for a Norma and Jerol Sonosky summer fellowship to A.C. We thank Catherine Bridges for the synthesis of a batch of ligand precursor. We are grateful to NSF (grant CRIF 1048807) and USC for their sponsorship of NMR spectrometers and X-ray diffractometer. We are grateful to Anton Burg Foundation for their sponsorship of the elemental analysis instrument. The authors declare no competing financial interest.

Attached Files

Supplemental Material - ja6b01980_si_001.pdf

Supplemental Material - ja6b01980_si_002.pdf

Files

ja6b01980_si_001.pdf
Files (9.9 MB)
Name Size Download all
md5:793ecc90ef743a3ec52d2760bb0516ff
5.2 MB Preview Download
md5:c8a4ef797270b3ec53e14662e4bb775f
4.8 MB Preview Download

Additional details

Created:
August 20, 2023
Modified:
October 18, 2023